40,000‑Year‑Old RNA from Yuka the Mammoth Reveals Clues to Its Final Moments

Ancient RNA from a juvenile woolly mammoth sheds light on its last moments

Scientists have recovered and sequenced the oldest-known RNA to date from a juvenile woolly mammoth named Yuka, whose mummified leg was unearthed in 2010 at Oyogos Yar in northeastern Siberia. Preserved in permafrost for roughly 40,000 years, the tissue produced molecular traces that reveal which genes were active in the animal’s cells near the time of death.

The team examined ten frozen mammoth tissue samples (muscle and skin). RNA fragments were detectable in three samples, but only Yuka’s leg yielded sequencing data detailed enough to reconstruct both messenger RNA (mRNA) and microRNA profiles.

"All the cells in an organism, they have the same DNA, a brain cell or a liver cell or muscle cell. So what makes these cells different from each other is essentially the RNA,"

— Love Dalén, professor of evolutionary genomics at the Centre for Palaeogenetics and the Swedish Museum of Natural History, and senior author of the study published in Cell.

What the RNA shows

From the sequencing data, researchers identified mRNA (which encodes proteins) and microRNA (small molecules that regulate gene activity). The molecular signature indicated a predominance of slow‑twitch muscle fibers in the sampled tissue and the presence of muscle-related proteins such as titin (linked to muscle elasticity) and nebulin (involved in skeletal muscle contraction). The authors suggest these signals may reflect active muscle metabolism and "final pulses" at or near the time of death.

"We do hypothesize that this animal was close to death, and this is manifested in the metabolism of the muscle," said Emilio Mármol Sánchez, the study’s lead author and a postdoctoral researcher at the Globe Institute, University of Copenhagen.

Significance and caveats

This work marks a major technical achievement: detecting tissue-specific gene expression in an organism that lived tens of thousands of years ago. Coauthor Marc Friedländer emphasized that muscle-specific microRNAs are direct evidence of regulatory activity preserved in ancient tissue.

Experts not involved in the study, such as Erez Lieberman Aiden, noted the result is biologically plausible and technically impressive, but cautioned that the methods currently rely on exceptionally well-preserved samples. Of the ten tissues tested by the team, only three contained RNA fragments and only one produced high-quality sequencing data, so broader applicability is not yet established.

Broader implications

If techniques improve and can be applied to more specimens, ancient RNA sequencing could open new research avenues: studying the evolution of RNA viruses, tracing pathogen histories beyond bacteria (for which DNA has already been informative), and potentially refining targets for genetic-editing approaches related to de-extinction efforts. Love Dalén — who advises Colossal Biosciences, a company working on revival-like projects — noted the methods might help identify genes of interest for editing, though such efforts remain scientifically and ethically complex.

Previous studies have recovered RNA from younger or better-preserved specimens, including a 130‑year‑old thylacine (Tasmanian tiger), a 14,300‑year‑old permafrost wolf, and RNA traces in Ötzi the Iceman, but Yuka’s RNA is the oldest to yield informative sequencing to date.

Conclusion

The study represents a significant step forward for palaeogenetics, demonstrating that RNA can survive under rare, favorable conditions and carry biologically meaningful information about an organism’s state at death. However, routine recovery of such data will likely require further methodological advances and a steady supply of exceptionally preserved material.

Published in: Cell. Lead authors: Emilio Mármol Sánchez; Senior author: Love Dalén; Coauthor: Marc Friedländer.